chiark / gitweb /
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[elogind.git] / man / journalctl.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
5 <!--
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7
8   Copyright 2012 Lennart Poettering
9
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22 -->
23
24 <refentry id="journalctl">
25
26         <refentryinfo>
27                 <title>journalctl</title>
28                 <productname>systemd</productname>
29
30                 <authorgroup>
31                         <author>
32                                 <contrib>Developer</contrib>
33                                 <firstname>Lennart</firstname>
34                                 <surname>Poettering</surname>
35                                 <email>lennart@poettering.net</email>
36                         </author>
37                 </authorgroup>
38         </refentryinfo>
39
40         <refmeta>
41                 <refentrytitle>journalctl</refentrytitle>
42                 <manvolnum>1</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>journalctl</refname>
47                 <refpurpose>Query the systemd journal</refpurpose>
48         </refnamediv>
49
50         <refsynopsisdiv>
51                 <cmdsynopsis>
52                         <command>journalctl</command>
53                         <arg choice="opt" rep="repeat">OPTIONS</arg>
54                         <arg choice="opt" rep="repeat">MATCHES</arg>
55                 </cmdsynopsis>
56         </refsynopsisdiv>
57
58         <refsect1>
59                 <title>Description</title>
60
61                 <para><command>journalctl</command> may be used to
62                 query the contents of the
63                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
64                 journal as written by
65                 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
66
67                 <para>If called without parameters, it will show the full
68                 contents of the journal, starting with the oldest
69                 entry collected.</para>
70
71                 <para>If one or more match arguments are passed, the
72                 output is filtered accordingly. A match is in the
73                 format <literal>FIELD=VALUE</literal>,
74                 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
75                 referring to the components of a structured journal
76                 entry. See
77                 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
78                 for a list of well-known fields. If multiple matches
79                 are specified matching different fields, the log
80                 entries are filtered by both, i.e. the resulting output
81                 will show only entries matching all the specified
82                 matches of this kind. If two matches apply to the same
83                 field, then they are automatically matched as
84                 alternatives, i.e. the resulting output will show
85                 entries matching any of the specified matches for the
86                 same field. Finally, if the character
87                 <literal>+</literal> appears as separate word on the
88                 command line, all matches before and after are combined
89                 in a disjunction (i.e. logical OR).</para>
90
91                 <para>As shortcuts for a few types of field/value
92                 matches, file paths may be specified. If a file path
93                 refers to an executable file, this is equivalent to an
94                 <literal>_EXE=</literal> match for the canonicalized
95                 binary path. Similarly, if a path refers to a device
96                 node, this is equivalent to a
97                 <literal>_KERNEL_DEVICE=</literal> match for the
98                 device.</para>
99
100                 <para>Output is interleaved from all accessible
101                 journal files, whether they are rotated or currently
102                 being written, and regardless of whether they belong to the
103                 system itself or are accessible user journals.</para>
104
105                 <para>All users are granted access to their private
106                 per-user journals. However, by default, only root and
107                 users who are members of the <literal>adm</literal>
108                 group get access to the system journal and the
109                 journals of other users.</para>
110
111                 <para>The output is paged through
112                 <command>less</command> by default, and long lines are
113                 "truncated" to screen width. The hidden part can be
114                 viewed by using the left-arrow and right-arrow
115                 keys. Paging can be disabled, see
116                 <option>--no-pager</option> and section Environment
117                 below.</para>
118
119                 <para>When outputing to a tty, lines are colored
120                 according to priority: lines of level ERROR and higher
121                 are colored red, lines of level NOTICE and higher are
122                 highlighted, and other lines are displayed normally.
123                 </para>
124         </refsect1>
125
126         <refsect1>
127                 <title>Options</title>
128
129                 <para>The following options are understood:</para>
130
131                 <variablelist>
132                         <varlistentry>
133                                 <term><option>-h</option></term>
134                                 <term><option>--help</option></term>
135
136                                 <listitem><para>Prints a short help
137                                 text and exits.</para></listitem>
138                         </varlistentry>
139
140                         <varlistentry>
141                                 <term><option>--version</option></term>
142
143                                 <listitem><para>Prints a short version
144                                 string and exits.</para></listitem>
145                         </varlistentry>
146
147                         <varlistentry>
148                                 <term><option>--no-pager</option></term>
149
150                                 <listitem><para>Do not pipe output into a
151                                 pager.</para></listitem>
152                         </varlistentry>
153
154                         <varlistentry>
155                                 <term><option>-l</option></term>
156                                 <term><option>--full</option></term>
157
158                                 <listitem><para>Show all (printable) fields in
159                                 full.</para></listitem>
160                         </varlistentry>
161
162                         <varlistentry>
163                                 <term><option>-a</option></term>
164                                 <term><option>--all</option></term>
165
166                                 <listitem><para>Show all fields in
167                                 full, even if they include unprintable
168                                 characters or are very
169                                 long.</para></listitem>
170                         </varlistentry>
171
172                         <varlistentry>
173                                 <term><option>-f</option></term>
174                                 <term><option>--follow</option></term>
175
176                                 <listitem><para>Show only the most recent
177                                 journal entries, and continuously print
178                                 new entries as they are appended to
179                                 the journal.</para></listitem>
180                         </varlistentry>
181
182                         <varlistentry>
183                                 <term><option>-e</option></term>
184                                 <term><option>--pager-end</option></term>
185
186                                 <listitem><para>Immediately jump to
187                                 the end of the journal inside the
188                                 implied pager tool. This implies
189                                 <option>-n1000</option> to guarantee
190                                 that the pager will not buffer logs of
191                                 unbounded size. This may be overridden
192                                 with an explicit <option>-n</option>
193                                 with some other numeric value on the
194                                 command line. Note that this option is
195                                 only supported for the
196                                 <citerefentry><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
197                                 pager.</para></listitem>
198                         </varlistentry>
199
200                         <varlistentry>
201                                 <term><option>-n</option></term>
202                                 <term><option>--lines=</option></term>
203
204                                 <listitem><para>Show the most recent
205                                 journal events and limit the number of
206                                 events shown. If
207                                 <option>--follow</option> is used,
208                                 this option is implied. The argument,
209                                 a positive integer, is optional, and
210                                 defaults to 10. </para></listitem>
211                         </varlistentry>
212
213                         <varlistentry>
214                                 <term><option>--no-tail</option></term>
215
216                                 <listitem><para>Show all stored output
217                                 lines, even in follow mode. Undoes the
218                                 effect of
219                                 <option>--lines=</option>.</para></listitem>
220                         </varlistentry>
221
222                         <varlistentry>
223                                 <term><option>-r</option></term>
224                                 <term><option>--reverse</option></term>
225
226                                 <listitem><para>Reverse output, so the newest
227                                 entries are displayed first.</para></listitem>
228                         </varlistentry>
229
230                         <varlistentry>
231                                 <term><option>-o</option></term>
232                                 <term><option>--output=</option></term>
233
234                                 <listitem><para>Controls the
235                                 formatting of the journal entries that
236                                 are shown. Takes one of the following options:
237                                 </para>
238                                 <variablelist>
239                                         <varlistentry>
240                                                 <term>
241                                                         <option>short</option>
242                                                 </term>
243                                                 <listitem>
244                                                         <para>is the default
245                                                         and generates an output
246                                                         that is mostly identical
247                                                         to the formatting of
248                                                         classic syslog files,
249                                                         showing one line per
250                                                         journal entry.</para>
251                                                 </listitem>
252                                         </varlistentry>
253
254                                         <varlistentry>
255                                                 <term>
256                                                         <option>short-iso</option>
257                                                 </term>
258                                                 <listitem>
259                                                         <para>is very similar,
260                                                         but shows ISO 8601
261                                                         wallclock timestamps.
262                                                         </para>
263                                                 </listitem>
264                                         </varlistentry>
265
266                                         <varlistentry>
267                                                 <term>
268                                                         <option>short-precise</option>
269                                                 </term>
270                                                 <listitem>
271                                                         <para>is very similar,
272                                                         but shows timestamps
273                                                         with full microsecond
274                                                         precision.
275                                                         </para>
276                                                 </listitem>
277                                         </varlistentry>
278
279                                         <varlistentry>
280                                                 <term>
281                                                         <option>short-monotonic</option>
282                                                 </term>
283                                                 <listitem>
284                                                         <para>is very similar
285                                                         but shows monotonic
286                                                         timestamps instead of
287                                                         wallclock timestamps.
288                                                         </para>
289                                                 </listitem>
290                                         </varlistentry>
291
292                                         <varlistentry>
293                                                 <term>
294                                                         <option>verbose</option>
295                                                 </term>
296                                                 <listitem>
297                                                         <para>shows the
298                                                         full-structured entry
299                                                         items with all fields.
300                                                         </para>
301                                                 </listitem>
302                                         </varlistentry>
303
304                                         <varlistentry>
305                                                 <term>
306                                                         <option>export</option>
307                                                 </term>
308                                                 <listitem>
309                                                         <para>serializes the
310                                                         journal into a binary
311                                                         (but mostly text-based)
312                                                         stream suitable for
313                                                         backups and network
314                                                         transfer (see <ulink
315                                                         url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
316                                                         Export Format</ulink>
317                                                         for more
318                                                         information).</para>
319                                                 </listitem>
320                                         </varlistentry>
321
322                                         <varlistentry>
323                                                 <term>
324                                                         <option>json</option>
325                                                 </term>
326                                                 <listitem>
327                                                         <para>formats entries
328                                                         as JSON data structures,
329                                                         one per line (see <ulink
330                                                         url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
331                                                         JSON Format</ulink> for
332                                                         more information).</para>
333                                                 </listitem>
334                                         </varlistentry>
335
336                                         <varlistentry>
337                                                 <term>
338                                                         <option>json-pretty</option>
339                                                 </term>
340                                                 <listitem>
341                                                         <para>formats entries as
342                                                         JSON data structures,
343                                                         but formats them in
344                                                         multiple lines in order
345                                                         to make them more
346                                                         readable for humans.</para>
347                                                 </listitem>
348                                         </varlistentry>
349
350                                         <varlistentry>
351                                                 <term>
352                                                         <option>json-sse</option>
353                                                 </term>
354                                                 <listitem>
355                                                         <para>formats entries as
356                                                         JSON data structures,
357                                                         but wraps them in a
358                                                         format suitable for <ulink
359                                                         url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
360                                                         Events</ulink>.</para>
361                                                 </listitem>
362                                         </varlistentry>
363
364                                         <varlistentry>
365                                                 <term>
366                                                         <option>cat</option>
367                                                 </term>
368                                                 <listitem>
369                                                         <para>generates a very
370                                                         terse output only
371                                                         showing the actual
372                                                         message of each journal
373                                                         entry with no meta data,
374                                                         not even a timestamp.
375                                                         </para>
376                                                 </listitem>
377                                         </varlistentry>
378                                 </variablelist>
379                                 </listitem>
380                         </varlistentry>
381
382                         <varlistentry>
383                                 <term><option>-x</option></term>
384                                 <term><option>--catalog</option></term>
385
386                                 <listitem><para>Augment log lines with
387                                 explanation texts from the message
388                                 catalog. This will add explanatory
389                                 help texts to log messages in the
390                                 output where this is available. These
391                                 short help texts will explain the
392                                 context of an error or log event,
393                                 possible solutions, as well as
394                                 pointers to support forums, developer
395                                 documentation and any other relevant
396                                 manuals. Note that help texts are not
397                                 available for all messages, but only
398                                 for selected ones. For more
399                                 information on the message catalog,
400                                 please refer to the <ulink
401                                 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
402                                 Catalog Developer
403                                 Documentation</ulink>.</para></listitem>
404                         </varlistentry>
405
406                         <varlistentry>
407                                 <term><option>-q</option></term>
408                                 <term><option>--quiet</option></term>
409
410                                 <listitem><para>Suppresses any warning
411                                 message regarding inaccessible system
412                                 journals when run as normal
413                                 user.</para></listitem>
414                         </varlistentry>
415
416                         <varlistentry>
417                                 <term><option>-m</option></term>
418                                 <term><option>--merge</option></term>
419
420                                 <listitem><para>Show entries
421                                 interleaved from all available
422                                 journals, including remote
423                                 ones.</para></listitem>
424                         </varlistentry>
425
426                         <varlistentry>
427                                 <term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>┬▒offset</replaceable></optional></option></term>
428                                 <term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>┬▒offset</replaceable></optional></option></term>
429
430                                 <listitem><para>Show messages from a specific
431                                 boot. This will add a match for
432                                 <literal>_BOOT_ID=</literal>.</para>
433
434                                 <para>The argument may be empty, in which case
435                                 logs for the current boot will be shown.</para>
436
437                                 <para>If the boot ID is omitted, a positive
438                                 <replaceable>offset</replaceable> will look up
439                                 the boots starting from the beginning of the
440                                 journal, and a equal-or-less-than zero
441                                 <replaceable>offset</replaceable> will look up
442                                 boots starting from the end of the
443                                 journal. Thus, <constant>1</constant> means the
444                                 first boot found in the journal in the
445                                 chronological order, <constant>2</constant> the
446                                 second and so on; while <constant>-0</constant>
447                                 is the last boot, <constant>-1</constant> the
448                                 boot before that, and so on. An empty
449                                 <replaceable>offset</replaceable> is equivalent
450                                 to specifying <constant>-0</constant>, except
451                                 when the current boot is not the last boot
452                                 (e.g. because <option>--directory</option> was
453                                 specified to look at logs from a different
454                                 machine).</para>
455
456                                 <para>If the 32 character
457                                 <replaceable>ID</replaceable> is specified, it
458                                 may optionally be followed by
459                                 <replaceable>offset</replaceable> which
460                                 identifies the boot relative to the one given by
461                                 boot <replaceable>ID</replaceable>. Negative
462                                 values mean earlier boots and a positive values
463                                 mean later boots. If
464                                 <replaceable>offset</replaceable> is not
465                                 specified, a value of zero is assumed and the
466                                 logs for the boot given by
467                                 <replaceable>ID</replaceable> are shown.
468                                 </para>
469
470                                 </listitem>
471                         </varlistentry>
472
473                         <varlistentry>
474                                 <term><option>-k</option></term>
475                                 <term><option>--dmesg</option></term>
476
477                                 <listitem><para>Show only kernel messages. This
478                                 implies <option>-b</option> and adds the match
479                                 <literal>_TRANSPORT=kernel</literal>.
480                                 </para></listitem>
481                         </varlistentry>
482
483                         <varlistentry>
484                                 <term><option>-u</option></term>
485                                 <term><option>--unit=</option></term>
486
487                                 <listitem><para>Show messages for the
488                                 specified systemd unit. This will add
489                                 a match for messages from the unit
490                                 (<literal>_SYSTEMD_UNIT=</literal>)
491                                 and additional matches for messages
492                                 from systemd and messages about
493                                 coredumps for the specified unit.</para>
494                                 <para>This parameter can be specified multiple times.
495                                 </para></listitem>
496                         </varlistentry>
497
498                         <varlistentry>
499                                 <term><option>--user-unit=</option></term>
500
501                                 <listitem><para>Show messages for the
502                                 specified user session unit. This will
503                                 add a match for messages from the unit
504                                 (<literal>_SYSTEMD_USER_UNIT=</literal>
505                                 and <literal>_UID=</literal>) and
506                                 additional matches for messages from
507                                 session systemd and messages about
508                                 coredumps for the specified unit.</para>
509                                 <para>This parameter can be specified multiple times.
510                                 </para></listitem>
511                         </varlistentry>
512
513                         <varlistentry>
514                                 <term><option>-p</option></term>
515                                 <term><option>--priority=</option></term>
516
517                                 <listitem><para>Filter output by
518                                 message priorities or priority
519                                 ranges. Takes either a single numeric
520                                 or textual log level (i.e. between
521                                 0/<literal>emerg</literal> and
522                                 7/<literal>debug</literal>), or a
523                                 range of numeric/text log levels in
524                                 the form FROM..TO. The log levels are
525                                 the usual syslog log levels as
526                                 documented in
527                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
528                                 i.e. <literal>emerg</literal> (0),
529                                 <literal>alert</literal> (1),
530                                 <literal>crit</literal> (2),
531                                 <literal>err</literal> (3),
532                                 <literal>warning</literal> (4),
533                                 <literal>notice</literal> (5),
534                                 <literal>info</literal> (6),
535                                 <literal>debug</literal> (7). If a
536                                 single log level is specified, all
537                                 messages with this log level or a
538                                 lower (hence more important) log level
539                                 are shown. If a range is specified, all
540                                 messages within the range are shown,
541                                 including both the start and the end
542                                 value of the range. This will add
543                                 <literal>PRIORITY=</literal> matches
544                                 for the specified
545                                 priorities.</para></listitem>
546                         </varlistentry>
547
548                         <varlistentry>
549                                 <term><option>-c</option></term>
550                                 <term><option>--cursor=</option></term>
551
552                                 <listitem><para>Start showing entries
553                                 from the location in the journal
554                                 specified by the passed
555                                 cursor.</para></listitem>
556                         </varlistentry>
557
558                         <varlistentry>
559                                 <term><option>--after-cursor=</option></term>
560
561                                 <listitem><para>Start showing entries from the
562                                 location in the journal
563                                 <emphasis>after</emphasis> the location
564                                 specified by the this cursor.
565                                 </para></listitem>
566                         </varlistentry>
567
568                         <varlistentry>
569                                 <term><option>--since=</option></term>
570                                 <term><option>--until=</option></term>
571
572                                 <listitem><para>Start showing entries
573                                 on or newer than the specified date,
574                                 or on or older than the specified
575                                 date, respectively. Date specifications
576                                 should be of the format
577                                 <literal>2012-10-30 18:17:16</literal>.
578                                 If the time part is omitted,
579                                 <literal>00:00:00</literal> is assumed.
580                                 If only the seconds component is omitted,
581                                 <literal>:00</literal> is assumed. If the
582                                 date component is omitted, the current
583                                 day is assumed. Alternatively the strings
584                                 <literal>yesterday</literal>,
585                                 <literal>today</literal>,
586                                 <literal>tomorrow</literal> are
587                                 understood, which refer to 00:00:00 of
588                                 the day before the current day, the
589                                 current day, or the day after the
590                                 current day, respectively. <literal>now</literal>
591                                 refers to the current time. Finally,
592                                 relative times may be specified,
593                                 prefixed with <literal>-</literal> or
594                                 <literal>+</literal>, referring to
595                                 times before or after the current
596                                 time, respectively.</para></listitem>
597                         </varlistentry>
598
599                         <varlistentry>
600                                 <term><option>-F</option></term>
601                                 <term><option>--field=</option></term>
602
603                                 <listitem><para>Print all possible
604                                 data values the specified field can
605                                 take in all entries of the
606                                 journal.</para></listitem>
607                         </varlistentry>
608
609                         <varlistentry>
610                                 <term><option>--system</option></term>
611                                 <term><option>--user</option></term>
612
613                                 <listitem><para>Show messages from
614                                 system services and the kernel (with
615                                 <option>--system</option>).  Show
616                                 messages from service of current user
617                                 (with <option>--user</option>).
618                                 If neither is specified, show all
619                                 messages that the user can see.
620                                 </para></listitem>
621                         </varlistentry>
622
623                         <varlistentry>
624                                 <term><option>-D <replaceable>DIR</replaceable></option></term>
625                                 <term><option>--directory=<replaceable>DIR</replaceable></option></term>
626
627                                 <listitem><para>Takes a directory path
628                                 as argument. If specified, journalctl
629                                 will operate on the specified journal
630                                 directory
631                                 <replaceable>DIR</replaceable> instead
632                                 of the default runtime and system
633                                 journal paths.</para></listitem>
634                         </varlistentry>
635
636                         <varlistentry>
637                                 <term><option>--file=<replaceable>GLOB</replaceable></option></term>
638
639                                 <listitem><para>Takes a file glob as
640                                 argument. If specified, journalctl will
641                                 operate on the specified journal files
642                                 matching <replaceable>GLOB</replaceable>
643                                 instead of the default runtime and
644                                 system journal paths. May be specified
645                                 multiple times, in which case files will
646                                 be suitably interleaved.</para></listitem>
647                         </varlistentry>
648
649                         <varlistentry>
650                                 <term><option>--root=<replaceable>ROOT</replaceable></option></term>
651
652                                 <listitem><para>Takes a directory path
653                                 as argument. If specified, journalctl
654                                 will operate on catalog file hierarchy
655                                 underneath the specified directory
656                                 instead of the root directory
657                                 (e.g. <option>--update-catalog</option>
658                                 will create
659                                 <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
660                                 </para></listitem>
661                         </varlistentry>
662
663                         <varlistentry>
664                                 <term><option>--new-id128</option></term>
665
666                                 <listitem><para>Instead of showing
667                                 journal contents, generate a new 128
668                                 bit ID suitable for identifying
669                                 messages. This is intended for usage
670                                 by developers who need a new
671                                 identifier for a new message they
672                                 introduce and want to make
673                                 recognizable. This will print the new ID in
674                                 three different formats which can be
675                                 copied into source code or
676                                 similar.</para></listitem>
677                         </varlistentry>
678
679                         <varlistentry>
680                                 <term><option>--header</option></term>
681
682                                 <listitem><para>Instead of showing
683                                 journal contents, show internal header
684                                 information of the journal fields
685                                 accessed.</para></listitem>
686                         </varlistentry>
687
688                         <varlistentry>
689                                 <term><option>--disk-usage</option></term>
690
691                                 <listitem><para>Shows the current disk
692                                 usage of all
693                                 journal files.</para></listitem>
694                         </varlistentry>
695
696                         <varlistentry>
697                                 <term><option>--list-catalog
698                                 <optional><replaceable>ID128...</replaceable></optional>
699                                 </option></term>
700
701                                 <listitem><para>List the contents of
702                                 the message catalog, as table of
703                                 message IDs plus their short
704                                 description strings.</para>
705
706                                 <para>If any
707                                 <replaceable>ID128</replaceable>s are
708                                 specified, only those entries are shown.
709                                 </para>
710                                 </listitem>
711                         </varlistentry>
712
713                         <varlistentry>
714                                 <term><option>--dump-catalog
715                                 <optional><replaceable>ID128...</replaceable></optional>
716                                 </option></term>
717
718                                 <listitem><para>Show the contents of
719                                 the message catalog, with entries
720                                 separated by a line consisting of two
721                                 dashes and the id (the format is the
722                                 same as <filename>.catalog</filename>
723                                 files.</para>
724
725                                 <para>If any
726                                 <replaceable>ID128</replaceable>s are
727                                 specified, only those entries are shown.
728                                 </para>
729                                 </listitem>
730                         </varlistentry>
731
732                         <varlistentry>
733                                 <term><option>--update-catalog</option></term>
734
735                                 <listitem><para>Update the message
736                                 catalog index. This command needs to
737                                 be executed each time new catalog
738                                 files are installed, removed or
739                                 updated to rebuild the binary catalog
740                                 index.</para></listitem>
741                         </varlistentry>
742
743                         <varlistentry>
744                                 <term><option>--setup-keys</option></term>
745
746                                 <listitem><para>Instead of showing
747                                 journal contents, generate a new key
748                                 pair for Forward Secure Sealing
749                                 (FSS). This will generate a sealing
750                                 key and a verification key. The
751                                 sealing key is stored in the journal
752                                 data directory and shall remain on the
753                                 host. The verification key should be
754                                 stored externally. Also see the
755                                 <option>Seal=</option> option in
756                                 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
757                                 for details.</para></listitem>
758                         </varlistentry>
759
760                         <varlistentry>
761                                 <term><option>--force</option></term>
762
763                                 <listitem><para>When --setup-keys is passed and
764                                 Forward Secure Sealing has already been set up,
765                                 recreate FSS keys.</para></listitem>
766                         </varlistentry>
767
768                         <varlistentry>
769                                 <term><option>--interval=</option></term>
770
771                                 <listitem><para>Specifies the change
772                                 interval for the sealing key when
773                                 generating an FSS key pair with
774                                 <option>--setup-keys</option>. Shorter
775                                 intervals increase CPU consumption but
776                                 shorten the time range of
777                                 undetectable journal
778                                 alterations. Defaults to
779                                 15min.</para></listitem>
780                         </varlistentry>
781
782                         <varlistentry>
783                                 <term><option>--verify</option></term>
784
785                                 <listitem><para>Check the journal file
786                                 for internal consistency. If the
787                                 file has been generated with FSS
788                                 enabled and the FSS verification key
789                                 has been specified with
790                                 <option>--verify-key=</option>,
791                                 authenticity of the journal file is
792                                 verified.</para></listitem>
793                         </varlistentry>
794
795                         <varlistentry>
796                                 <term><option>--verify-key=</option></term>
797
798                                 <listitem><para>Specifies the FSS
799                                 verification key to use for the
800                                 <option>--verify</option>
801                                 operation.</para></listitem>
802                         </varlistentry>
803
804                 </variablelist>
805         </refsect1>
806
807         <refsect1>
808                 <title>Exit status</title>
809
810                 <para>On success, 0 is returned, a non-zero failure
811                 code otherwise.</para>
812         </refsect1>
813
814         <refsect1>
815                 <title>Environment</title>
816
817                 <variablelist class='environment-variables'>
818                         <varlistentry>
819                                 <term><varname>$SYSTEMD_PAGER</varname></term>
820                                 <listitem><para>Pager to use when
821                                 <option>--no-pager</option> is not given;
822                                 overrides <varname>$PAGER</varname>.  Setting
823                                 this to an empty string or the value
824                                 <literal>cat</literal> is equivalent to passing
825                                 <option>--no-pager</option>.</para></listitem>
826                         </varlistentry>
827                 </variablelist>
828         </refsect1>
829
830         <refsect1>
831                 <title>Examples</title>
832
833                 <para>Without arguments, all collected logs are shown
834                 unfiltered:</para>
835
836                 <programlisting>journalctl</programlisting>
837
838                 <para>With one match specified, all entries with a field matching the expression are shown:</para>
839
840                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
841
842                 <para>If two different fields are matched, only entries matching both expressions at the same time are shown:</para>
843
844                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
845
846                 <para>If two matches refer to the same field, all entries matching either expression are shown:</para>
847
848                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
849
850                 <para>If the separator <literal>+</literal> is used,
851                 two expressions may be combined in a logical OR. The
852                 following will show all messages from the Avahi
853                 service process with the PID 28097 plus all messages
854                 from the D-Bus service (from any of its
855                 processes):</para>
856
857                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
858
859                 <para>Show all logs generated by the D-Bus executable:</para>
860
861                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
862
863                 <para>Show all logs of the kernel device node <filename noindex='true'>/dev/sda</filename>:</para>
864
865                 <programlisting>journalctl /dev/sda</programlisting>
866
867                 <para>Show all kernel logs from previous boot:</para>
868
869                 <programlisting>journalctl -k -b -1</programlisting>
870
871         </refsect1>
872
873         <refsect1>
874                 <title>See Also</title>
875                 <para>
876                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
877                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
878                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
879                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
880                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
881                 </para>
882         </refsect1>
883
884 </refentry>